
// 96.不同的二叉搜索树
class Solution {
public:
    int numTrees(int n) {
        vector<int> dp(n + 1);
        dp[0] = 1;

        //  dp[j] = dp[j - 1]*dp[i - j]
        for(int i = 1; i <= n ;i++)
            for(int j = 1; j <= i ; j++)
                dp[i] += dp[j - 1]*dp[i - j];
        return dp[n];
    }
};